The prevention and treatment of oral diseases, such as gingivitis, periodontitis and dental caries, typically are much more difficult during a course of orthodontic treatment than at other times, for reasons which are quite apparent. The continuous presence of brackets, wires and other orthodontic paraphernalia in the mouth interferes with normal oral hygiene.
It is well known that dental disease is caused in major part by failure to frequently and completely remove food residues from positions against the teeth and gums, and/or by the presence of accumulated plaque. Removal of food residues is very important if dental caries and gum disease are to be avoided. And, accumulation of plaque on teeth is particularly undesirable because it leads to gingivitis, which, in turn, may progress to periodontitis.
Orthodontic braces in certain situations make it difficult at best to reach and remove food and to remove or control plaque by the normal mechanical techniques, such as brushing, flossing, and water irrigating. Tooth brush bristles cannot readily reach all areas of the teeth, and dental floss cannot reach the areas between the teeth adjacent to the gums or portions of the gingival sulci.
Not only are mechanical cleaning procedures impeded or blocked, but orthodontic braces are by nature food traps which predispose the teeth to development of dental caries and accumulation of plaque. Furthermore, the shifting of tooth positions during orthodontic treatment itself further predisposes a patient to development of gingivitis.
Because of difficulty of mechanical cleaning during a course of orthodontic treatment, chemical cleaning and plaque control take on greater importance.
A wide variety of dentally-active pharmacological agents are known, including antiseptic agents, antiplaque agents and anticaries agents. Examples include: certain halide salts, particularly specific fluorides and chlorides such as stannous fluoride, sodium fluoride, and sodium chloride; fluorides such as sodium fluoride with soluble pyrophosphates such as a mixture of tetrasodium pyrophosphate and disodium dihydrogen pyrophosphate; chlorhexidine digluconate; and sanguinarine.
While the nature of the dental therapeutic benefits of these examples need not be reviewed in detail here, a few comments may be helpful.
The anti-caries and anti-gingivitis effects of certain fluorides and chlorides are well known. Stannous fluoride is known to prevent plaque bonding and thus prevent plaque buildup. The soluble pyrophosphates have been shown, in combination with sodium fluoride, to enhance the interruption of the transformation of amorphous calcium phosphate into dental calculus.
Chlorhexidine digluconate, a water-soluble compound, has been shown to be effective against periodontal disease. It has a significant plaque-inhibiting effect, Contributes to plaque breakdown, and is a potent suppressor of Streptococcus Mutans, which is implicated in dental caries. It is known to be effective in reducing periodontal inflammation. Sanguinarine, which has an affinity for plaque, has been demonstrated to have a significant anti-plaque effect. It has been shown to be superior to certain other therapeutic agents in inhibiting salivary glycolysis, which is used as a predictor of the effectiveness of antiplaque agents.
These and other therapeutic agents may be applied to the teeth and gingiva in efficacious concentrations by means of toothpastes, mouthwashes and the like. However, such periodic applications may not completely reach the gingival sulci and other positions where disease is most likely, including tooth surfaces against which orthodontic paraphernalia is located. And, more significantly, such applications are transient, occurring between extended periods in which no therapeutic agent is introduced and previously introduced therapeutic agents are quickly diluted and dissipate.
Increasing the concentration of a dentally-active agent periodically introduced into the mouth, as in a mouthwash, may have the effect of extending somewhat the period of efficacy. But considering the lengthy period between successive introductions of such agents, even with a rigorous mouthwashing schedule, any such extending effect may not be very significant, unless the therapeutic agent has particular affinity for dental surfaces.
Furthermore, certain dentally-active pharmacological agents have negative side effects when introduced into the mouth or ingested in high concentrations, ruling out or limiting their use in such relatively high concentrations.
During a course of orthodontic treatment, the current practice is to introduce dentally-active pharmacological agents by mouthwashes several times daily. This practice overcomes the disadvantage of transience, mentioned above, only slightly, and only to the extent that frequency and regularity are emphasized to the inconvenience of the orthodontic patient.
Other means for introducing therapeutic agents into the intraoral environment have been proposed. Among these are the oral dispensing devices of U.S. Pat. Nos. 4,175,326 and 3,205,576, which relate to polymeric members having coatings or substances entrapped in spaces of various kinds such as the lumens of hollow fibers, surface caches, and the like. In such devices, the therapeutic substance will be released quickly in the intraoral environment and/or the release will be difficult to control. In some cases, not only could pharmacological agents be released much too quickly, but such agents, particularly certain agents, would be in too high a concentration in the mouth.
One critical characteristic of various orthodontic elastic polymeric members, such as elastic bands, elastomeric ligature ties or "threads," elastomeric chains, separators, super ties, and Steiner rotation wedges, is their elastic qualties--that is, their ability to apply force for various purposes in the mouth. Orthodontics involves the use of a variety of orthodontic braces, wires, and other orthodontic elements mounted in the mouth for the specific purpose of moving teeth away from positions of malocclusion. Such moving action itself and the appropriate securement of orthodontic paraphernalia are dependent on the force-applying ability of orthodontic elastic polymeric members. That is a principal reason why orthodontists replace such elastic polymeric members on a regular basis.
Replacement is required when the useful force-applying life of the elastic polymeric member, or much of such life, has passed. The length of such useful life is dependent on many factors. In the above-mentioned patents having polymeric members used to hold and dispense therapeutic substances, there is no correlation whatever between the release (typically very quick) of such substances and any force-applying capability for orthodontic purposes.
Indeed, U.S. Pat. No. 4,175,326 has polymeric members which are not elastic and therefore have no force-applying ability or life, or for that matter any orthodontic use.
Orthodontic elastic bands of the prior art have included flavoring. These include the coated bands of U.S. Pat. No. 3,205,576 mentioned above, the coating of which is released throughout the mouth in a "pump-like" action (col. 3, line 2), and the elastic bands of allowed copending Ser. No. 023,716, of Jeffery Fasnacht, an inventor herein, which have been in use. The latter include flavoring as an in situ constituent of elastic band formation from a homogeneous mixture of elastomer and flavoring substance.
There is a need for an improved orthodontic elastic polymeric member which, throughout its useful orthodontic force-applying life, provides a continuous acceptable level of therapeutic substance release immediately on the dental surface requiring such treatment, that is, immediately at the site of the orthodontic paraphernalia. There is a need for an improved method for prevention and treatment of dental disease during orthodontic treatment.